Barbara Mahler


Barbara grew up in northern California, where she learned to appreciate the value of water.  She received a B. Mus. in performance at Boston University; in 1986 she moved to Austin, Texas.  Combining her interest in water, mathematics, and the outdoors, she enrolled at the University of Texas and received her Masters and Ph.D. degrees in Geology, with an emphasis on karst hydrology.  Her principal research interests are water quality of karst systems and source and fate of contaminated sediment.


Barbara has Masters and doctoral degrees in Geology from the University of Texas, where she studied with Dr. Philip Bennett.  The emphasis of her graduate research was the geochemistry of karst aquifers.  Her doctoral research focused on sediment transport through karst aquifers and its potential to serve as a vector for contaminant transport.  After completing her Ph.D. in 1997, she spent 1 year as an NSF/NATO International Postdoc in Montpellier, France, studying transport of sediment and bacteria in karst. 

She began her career with the USGS (Texas Water Science Center) in 1998, where she is a Research Hydrologist.  She is part of the Contaminant Trends in Lake Sediments (CTLS) team, which uses cores of sediments from lakes to reconstruct the contaminant histories of watersheds.  The CTLS has identified nation-wide patterns of trends in metals and organic contaminants, including lead, DDT, and PAHs.  Barbara’s associated research with the CTLS has included identification and evaluation of contaminant sources and processes, including rooftop runoff, suspended sediment in streams, contaminated runoff from parking lots, and house dust.  The CTLS has been instrumental in identifying and quantifying the importance of coal-tar-based parking lot sealcoat as a source of PAHs at the national scale. 

In addition to her participation in the CTLS, Barbara continues her research on karst, with active projects in France and Texas, notably in the Barton Springs segment of the Edwards aquifer.  She helped redesign and update the USGS karst web page (  She is an Associate Editor for the Journal of Hydrology, and a member of the IAH Karst Hydrogeology Commission.  Her publications in the field of karst have included analysis of pesticide breakthrough curves in spring flow, use of nitrate as a tracer of recent recharge, and use of principal components analysis to investigate nutrient dynamics in karst.

Barbara is a Research Fellow at the University of Texas Jackson School of Geosciences.  She regularly serves on the committees of Masters and Ph.D. students, and on occasion teaches courses and lectures at the University.  She has supervised a number of student interns at the USGS.  She continues her collaborations with French scientists, notably Dr. Nicolas Massei.  In 2006 she spent a year in Rouen, and recently spent a month in Lyon working with the French environmental agency IRSTEA.  She is a regular reviewer for numerous scientific journals, including Journal of Hydrology, Hydrogeology Journal, Environmental Science and Technology, and Journal of Contaminant Hydrology.

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Mahler, B.J.; Woodside, M.D.; Van Metre, P.C., Coal-tar-based pavement sealcoat--Potential concerns for human health and aquatic life. USGS Fact Sheet 2016-3017. [Link]

Kienzler, A.; Mahler, B. J.; Van Metre, P. C.; Schweigert, N.; Devaux, A.; Bony, S., Exposure to runoff from coal-tar-sealed pavement induces genotoxicity and impairment of DNA repair capacity in the RTL-W1 fish liver cell line. Sci. Total Environ. 2015, 520, (1), 73-80. [Link]

Mahler, B. J.; Ingersoll, C. G.; Van Metre, P. C.; Kunz, J. L.; Little, E. E., Acute toxicity of runoff from sealcoated pavement to Ceriodaphnia dubia and Pimephales promelas. 2015. Environ. Sci. Technol. 49, (8), 5060-5069. [Link]

Mahler, B. J.; Van Metre, P. C.; Foreman, W. T., Concentrations of polycyclic aromatic hydrocarbons (PAHs) and azaarenes in runoff from coal-tar- and asphalt-sealcoated pavement. 2014. Envion. Pollut., 188, 81-87. [Link]

Mourier, B.; Desmet, M.; Van Metre, P. C.; Mahler, B. J.; Perrodin, Y.; Roux, G.; Bedell, J.-P.; Lefèvre, I.; Babut, M., Historical records, sources, and spatial trends of PCBs along the Rhône River (France). 2014. Science of the Total Environment, 476-477, 568-576.

Van Metre, P. C.; Mahler, B. J., PAH concentrations in lake sediment decline following ban on coal-tar-based pavement sealants in Austin, Texas. 2014. Environ. Sci. Technol., 48, 7222-7228. [Link]

Long, A. J.; Mahler, B. J., Predictability, stationarity, and classification of hydraulic responses to recharge in two karst aquifers. Hydrology and Earth Systems Science 2013, 17, 281-294. [Link]

Mahler, B. J.; Bourgeais, R., Dissolved oxygen fluctuations in karst spring flow and implications for endemic species: Barton Springs, Edwards Aquifer, Texas, USA. 2013. Journal of Hydrology, 505, 291-298. [Link]

Williams, E. S.; Mahler, B. J.; Van Metre, P. C., Cancer risk from incidental ingestion exposures to PAHs associated with coal-tar-sealed pavement. 2013. Environ. Sci. Technol., 47, (2), 1101-1109. [Link]

Van Metre, P.C., Majewski, M.S., Mahler, B.J., Foreman, W.T., Braun, C.L., Wilson, J.T., and Burbank, T.L. Volatilization of polycyclic aromatic hydrocarbons from coal-tar-sealed pavement. Chemosphere, 88(1):1-7. [Link]

Desmet, M., Mourier, B., Mahler, B.J., Van Metre, P., Roux, G., Persat, H., Lefèvre, Il, Peretti, A., Chapron, E., Simmonneau, A., Miège, C., and Babut, M. Spatial and temporal trends in PCBs in sediment along the lower Rhône River, France. Science of the Total Environment, 433:189-197.

Desmet, M.; Mourier, B.; Mahler, B. J.; Van Metre, P. C.; Roux, G.; Persat, H.; Lefèvre, I.; Peretti, A.; Chapron, E.; Simonneau, A.; Miège, C.; Babut, M., Spatial and temporal trends in PCBs in sediment along the lower Rhône River, France. 2012. Science of the Total Environment, 433, (0), 189-197

Van Metre, P. C.; Majewski, M. S.; Mahler, B. J.; Foreman, W. T.; Braun, C. L.; Wilson, J. T.; Burbank, T., PAH volatilization following application of coal-tar-based pavement sealant. 2012. Atmospheric Environment, 51, 108-115. [Link]

Williams, E. S.; Mahler, B. J.; Van Metre, P. C., Coal-tar pavement sealants may significantly increase children's PAH exposures. 2012. Environmental Pollution, 164, 40-41.

Wong, C. I.; Mahler, B. J.; Musgrove, M.; Banner, J. L., Changes in sources and storage in a karst aquifer during a transition from drought to wet conditions. 2012. Journal of Hydrology, 468-469, 159-172.[Link]

Mahler, B. J.; Musgrove, M.; Herrington, C. Nitrate concentrations and potential sources in the Barton Springs segment of the Edwards Aquifer and its contributing zone, Central Texas. 2011. USGS Fact Sheet 2011-3035. [Link]

Mahler, B. J.; Musgrove, M.; Herrington, C.; Sample, T. L. Recent (2008–10) concentrations and isotopic compositions of nitrate and concentrations of wastewater compounds in the Barton Springs Zone, South-Central Texas, and their potential relation to urban development in the contributing zone. 2011. USGS Scientific Investigations Report SIR 2011-5018 [Link]

Mahler, B. J.; Musgrove, M.; Wong, C. I.; Sample, T. L. Recent (2008–10) water quality in the Barton Springs segment of the Edwards Aquifer and its contributing zone, Central Texas, with emphasis on factors affecting nutrients and bacteria. 2011. USGS Scientific Investigations Report SIR 2011-5139 [Link]

Mahler, B. J.; Van Metre, P. C. Coal-tar-based pavement sealcoat, polycyclic aromatic hydrocarbons (PAHs), and environmental health. 2011. USGS Fact Sheet 2011-3010. [Link]

Yang, Y., Van Metre, P.C., Mahler, B.J., Wilson, J.T., Ligouis, B., Razzaque, M., Schaeffer, C., and Werth, C. The influence of coal-tar sealcoat and other carbonaceous materials on polycyclic aromatic hydrocarbon loading in an urban watershed. Environmental Science and Technology, 44(4): 1217-1223. [Link]

Van Metre, P.C., and Mahler, B.J. Contribution of PAHs from coal-tar pavement sealcoat and other sources to 40 U.S. Lakes. Science of the Total Environment, 409: 334-344. [Link]

Yang, Y., Mahler, B.J., Van Metre, P.C., Ligouis, B., and Werth, C.J. Potential contributions of asphalt and coal tar to black carbon quantification in urban dust, soils, and sediment. Geochemica et Cosmochimica Acta, 74(23):6830-6840.

Mahler, B. J.; Van Metre, P. C.; Wilson, J. T.; Musgrove, M.; Burbank, T. L.; Ennis, T. E.; Bashara, T. J., Coal-tar-based parking lot sealcoat: An unrecognized source of PAH to settled house dust. 2010. Environmental Science and Technology, 44, 894-900. [Link]

Mahler, B.J., Van Metre, P.C., Zaugg, S.D., Wilson, J.T., Musgrove, M., and Burkhardt, M.D. Fipronil and its degradates in indoor and outdoor dust. Environmental Science and Technology, 43: 5665-5670.[Link]

Mahler, B. J.; Garner, B. D., Using nitrate to quantify quick flow in a karst aquifer. 2009. Ground Water, 47, (3), 350-360.

Van Metre, P.C., Mahler, B.J., and Wilson, J.T. 2009. PAHs underfoot: Contaminated dust from sealcoated pavement. Environ. Sci. Technol., 43:20-25. [Download File]

Mahler, B.J., Valdes, D., Massei, N., and Musgrove, M. 2008. Nutrient dynamics as indicators of karst processes: Comparison of the Chalk aquifer (Normandy, France) and the Edwards aquifer (Texas, U.S.A.). J. Contam. Hydrol., 98: 36-49.

Mahler, B. J. Statistical analysis of major ion and trace element geochemistry of water, 1986–2006, at seven wells transecting the freshwater/saline-water interface of the Edwards aquifer, San Antonio, Texas. USGS Scientific Investigations Report SIR 2008-5224. [Link]

Van Metre, P. C.; Mahler, B. J.; Wilson, J. T.; Burbank, T. L. Collection and analysis of samples for polycyclic aromatic hydrocarbons in dust and other solids related to sealed and unsealed pavement from 10 cities across the United States, 2005-2007. 2008. USGS Data Series 361. [Link]

Garner, B.D., and Mahler, B.J., 2007, Relation of specific conductance in ground water to intersection of flow paths by wells, and associated major ion and nitrate geochemistry, Barton Springs segment of the Edwards aquifer, Austin, Texas, 1978–2003: U.S. Geological Survey Scientific Investigations Report 2007–5002, 39 p., 5 appendixes. [Link]

Mahler, B.J., and Massei, N., 2007, Anthropogenic contaminants as tracers in an urbanizing karst aquifer. J. Cont. Hydrol., 91: 81-106.

Massei, N.; Mahler, B. J.; Bakalowicz, M.; Fournier, M.; DuPont, J. P., Quantitative interpretation of conductivity frequency distributions in karst. Ground Water 2007, 45, (3), 288-293.

Frouin, M.; Sebag, D.; Durand, A.; Laignel, B.; Saliège, J.-F.; Mahler, B. J.; Fauchard, C., Influence of paleotopography, base level and sedimentation rate on estuarine system response to the Holocene sea-level rise: the example of the Marais Vernier, Seine Estuary, France. 2007. Sedimentary Geology, 200, (1-2), 15-29.

Valdes, D.; Dupont, J. P.; Laignel, B.; Ogier, S.; Leboulanger, T.; Mahler, B. J., A spatial analysis of structural controls on karst ground-water geochemistry at a regional scale. 2007. Journal of Hydrology.

Mahler, B.J., Garner, B.D., Musgrove, M., Guilfoyle, A.L., and Rao, M.V., 2006, Recent (2003–05) water quality of Barton Springs, Austin, Texas, with emphasis on factors affecting variability: U.S. Geological Survey ScientificInvestigations Report 2006–5299, 83 p., 5 appendixes. [Link]

Mahler, B. J.; Van Metre, P. C.; Wilson, J. T.; Guilfoyle, A. L.; Sunvison, M. W., 2006. Concentrations, Loads, and Yields of Particle-Associated Contaminants in Urban Creeks, Austin, Texas, 1999-2004. Geological Survey (U.S.) Scientific Investigations Report 2006-5262, viii, 107 p. [Link]

Van Metre, P. C.; Horowitz, A. J.; Mahler, B. J.; Foreman, W. T.; Fuller, C. C.; Burkhardt, M. R.; Elrick, K. A.; Furlong, E. T.; Skrobialowski, S. C.; Smith, J. J.; Wilson, J. T.; Zaugg, S. D., The effects of Hurricanes Katrina and Rita on the chemistry of bottom sediments in Lake Pontchartrain, Louisiana, USA. 2006. Environ. Sci. Technol., 40, (22), 6894-6902.

Massei, N.; DuPont, J. P.; Laignel, B.; Fournier, M.; Valdes, D.; Mahler, B. J.; Ogier, S., Investigating transport properties and turbidity dynamics of a karst aquifer using correlation, spectral, and wavelet analysis. 2006. Journal of Hydrology, 329, 244-257.

Mahler, B.J., Van Metre, P.C., and Callender, E. 2006. Trends in metals in urban and reference lake sediments across the United States, 1975-2001.Environ. Toxicol. Chem., 25: 1698-1709. [Download File]

Van Metre, Peter C.; Mahler, Barbara J.; Scoggins, Mateo; Hamilton, Pixie A., 2005. Parking lot sealcoat: a major source of polycyclic aromatic hydrocarbons (PAHs) in urban and suburban environments. Fact Sheet 2005-3147, 4 p. [Link]

Mahler, B.J., Van Metre, P.C., Bashara, T.J., Wilson, J.T., and Johns, D.A. 2005. Parking lot sealcoat: An unrecognized source of urban PAH. Environ. Sci. Technol., 39: 5560-5566.

Van Metre, P.C. and Mahler, B.J. 2005. Trends in hydrophobic organic contaminants in urban and reference lake sediments across the United States, 1970-2001. Environ. Sci. Technol., 39: 5567-5574.[Download File]

Van Metre, P. C.; Wilson, J. T.; Fuller, C. C.; Callender, E.; Mahler, B. J. Collection, analysis, and age-dating of sediment cores from 56 U.S. lakes and reservoirs sampled by the U.S. Geological Survey, 1992-2001. 2004. USGS Scientific Investigations Report SIR-2004-5184. [Link]

Mahler, B. J.; Van Metre, P. C.; Wilson, J. T. Concentrations of polycyclic aromatic hydrocarbons (PAHs) and major and trace elements in simulated rainfall runoff from parking lots, Austin, Texas, 2003. 2004. USGS Open-File Report OFR 2004-1208. [Link]

Personné, J. C.; Poty, F.; Mahler, B. J.; Drogue, C., Bacterial colonization of limestone in karst environments: In situ and laboratory experiments. 2004. Ground Water, 42, 526-533.

Van Metre, P.C., and Mahler, B.J. 2004. Contaminant trends in reservoir sediment cores as records of influent stream quality. Environ. Sci. Technol. 38: 2978-2986. [Download File]

Van Metre, P. C.; Wilson, J. T.; Harwell, G. R.; Gary, M. O.; Heitmuller, F. T.; Mahler, B. J. Occurrence, trends, and sources in particle-associated contaminants in selected streams and lakes in Fort Worth, Texas; 2003. USGS Water-Resources Investigations Report WRIR-03-4169. [Link]

Van Metre, P. C.; Jones, S. A.; Moring, J. B.; Wilson, J. T.; Mahler, B. J., Chemical quality of water, sediment, and fish in Mountain Creek Lake, Dallas, Texas, 1994-97. 2003. USGS Water-Resources Investigations Report WRIR-03-4082. [Link]

Mahler, B. J.; Van Metre, P. C., A chronicle of organochlorine contamination in Clear Creek, Galveston and Harris Counties, Texas, 1960-2002, as recorded in sediment cores. 2003. USGS Fact Sheet FS-088-03. [Link]

Mahler, B. J.; Van Metre, P. C., A simplified approach for monitoring of hydrophobic organic contaminants associated with suspended sediment-methodology and applications. 2003. Archives of Environmental Contamination and Toxicology, 44, 288-297.

Mahler, B. J. Quality of sediment discharging from the Barton Springs system, Austin, Texas, 2000-2002. 2003. USGS Fact Sheet FS-089-03. [Link]

Harwell, G. R.; Van Metre, P. C.; Wilson, J. T.; Mahler, B. J., Spatial distribution and trends in trace elements, polycyclic aromatic hydrocarbons, organochlorine pesticides, and polychlorinated biphenyls in Lake Worth sediment, Fort Worth, Texas. 2003. USGS Water-Resources Investigations Report SIR-03-4269. [Link]

Bruneel, O.; Personné, J. C.; Casiot, C.; Leblanc, M.; Elbaz-Poulichet, F.; Mahler, B. J.; LeFlèche, A.; Grimont, P. A. D., Thiomonas sp. mediated arsenic oxidation in acid mine drainages. 2003. Journal of Environmental Quality, 95, 492-499.

Van Metre, P.C., and Mahler, B.J. 2003. The contribution of particles washed from rooftops to contaminant loading to urban streams. Chemosphere, 52: 1727-1741. [Download File]

Massei, N.; Lacroix, M.; Wang, H. Q.; Mahler, B. J.; DuPont, J. P., Transport of suspended solids from a karstic to an alluvial aquifer: the role of the karst/alluvium interface. 2002. Journal of Hydrology, 260, (1-4), 88-101

Mahler, B. J.; Van Metre, P. C.; Miranda, R. M. Occurrence of polychlorinated biphenyls (PCBs) on suspended sediment in the Donna Canal, Hidalgo County, Texas, 1999-2001. 2002. USGS Fact Sheet FS-016-02. [Link]

Mahler, B. J.; Van Metre, P. C., Llano Grande lake bottom sediments – A chronicle of water-quality changes in the Arroyo Colorado, south Texas, 1989-2001. 2002. USFS Fact Sheet FS-065-02. [Link]

Mahler, B. J.; Gary, M. O.; Canova, M. G.; Strom, E. W.; Fahlquist, L.; Dorsey, M. E. Volatile Organic Compound and Pesticide Data for Public Water-Supply Reservoirs and Wells, Texas, 1999–2001. USGS Open-File Report OFR-02–093. [Link]

Mahler, B. J.; Canova, M. G.; Gary, M. O. Occurrence of Selected Volatile Organic Compounds and Soluble Pesticides in Texas Public Water-Supply Source Waters, 1999–2001. USGS Fact Sheet FS-020-02[Link]

Mahler, B. J.; Personné, J. C.; Lods, G. F.; Drogue, C., Transport of free and particulate-associated bacteria in karst. 2000. Journal of Hydrology, 238, 179-193.

Mahler, B. J., Determining the occurrence of pesticides and volatile organic compounds in public water-supply source waters in Texas. 2000. USGS Fact Sheet FS-010-00. [Link]

Van Metre, P.C., Mahler, B.J., and Furlong, E.T. 2000. Urban sprawl leaves its PAH signature. Environ. Sci. Technol., 34: 4064-4070. [Download File]

Mahler, B.J., and Lynch, F.L. 1999. Muddy waters: Temporal variation in sediment discharging from a karst spring. J. Hydrol., 214: 165-178.

Van Metre, P. C.; Mahler, B. J., Town Lake bottom sediments: A chronicle of water-quality changes in Austin, Texas, 1960-98. USGS Factsheet FS-183-99. [Link]

Mahler, B.J., Lynch, F.L., Bennett, P.C. 1998. Mobile sediment in an urbanizing karst aquifer: implications for contaminant transport. Environ. Geol., 39:25-39.

Mahler, B. J.; Winkler, M.; Bennett, P. C.; Hillis, D., DNA-labeled clay: a sensitive new method for tracing particle transport. 1998. Geology 26, 831-834.

Mahler, B. J.; Bennett, P. C.; Zimmerman, M., Lanthanide-labeled clay: A new method for tracing sediment transport in karst. 1998. Ground Water, 36, (5), 835-843.